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AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

Original poster

to ask non-scientists how they think snow globes work....

173 replies

M3lon · 17/07/2018 14:21

...and what would happen if there was no water or air in the globe with the glitter.

All for a good cause I promise!

OP posts:
Original poster
M3lon · 17/07/2018 21:28

The good cause I mentioned in the OP is an art/science outreach activity focussing on the arrow of time and our perception of the flow of time, and we are trying to work out how to pitch the explanations....and the best way to do that is to work out what people already think is happening.

I fear this will all feel anticlimactic....so if anyone has any other household item physics related mysteries then do ask away!

OP posts:
TheGherkin · 17/07/2018 21:28

I once drank a snow globe. It wasn’t nice,

Snickerdoodledandy · 17/07/2018 21:30

gherkin just-why?! Grin OP - it'd be good to ask groups of children different ages too.

Frankenterfer · 17/07/2018 21:31

I once drank a snow globe. It wasn’t nice,

Grin
Original poster
M3lon · 17/07/2018 21:36

Here's one....

Take a standard soft back book....wrap an elastic band around it so that pages can't flutter open.

Now hold the book by the two corners that have the spine between them. throw the book upwards and flip it like a pancake. It will do this just fine. Go for a full turn or even two turns if you can get enough spin...all fine.

Now turn the book so you are holding the bottom two corners, and attempt to do the same thing.......hint: you will probably fail to catch it the first time.

OP posts:
Original poster
M3lon · 17/07/2018 21:38

snicker yes - I will try and do that, its a good idea.

OP posts:
BertieBotts · 17/07/2018 21:47

I was really good at science at school but I am feeling completely clueless now Blush

I am interested in the time stuff, though, DH keeps trying to explain something about time to me and I can't get my head around it at all.

Wonkypalmtree · 17/07/2018 21:48

Fairy magic

TimeIhadaNameChange · 17/07/2018 21:50

Tried the book one. Caught it first time when holding it by the 'open' side, sorry!

Original poster
M3lon · 17/07/2018 21:54

I'm intrigued Bertie...what's he trying to tell you?

We are going at the perception of time through energy dissipation angle...so if you drop some food colour into warm water it will quickly go from a blob of dye to disappeared into the water by dispersing. If you saw that happening backward, all the dye coallescing from out of the water you would be really surprised and rightly suspect you were seeing a video played backwards.....so these thermodynamics driven processes show us the direction of time.

OP posts:
Original poster
M3lon · 17/07/2018 21:57

time good skills...but do you mean open side as in the side opposite the spine...because that wasn't the interesting side to throw it from.

a--b
| |
| |
| |
c--d

you need to try and flip it from holding c and d (or a and b). a and c or b and d are straight forward.

OP posts:
BertieBotts · 17/07/2018 21:58

TBH I am too sleepy and pregnant to really make sense of anything right now, but something about time not being a measurable thing but more fluid than we generally understand. Then something (probably unrelated) about how stopping time would basically cause a kind of loop where time runs over itself, like if you pulled two parts of a piece of cloth together and made them touch.

Original poster
M3lon · 17/07/2018 22:12

interesting! Hope you get good sleep - it must be a bit awful being pregnant in this heat!

OP posts:
Tanaqui · 17/07/2018 22:14

The book does lovely diagonal twirls- is that because of the weight of the spine compared with the unbound long edge?

RealMaryMagdalene · 17/07/2018 22:18

What age child are these lessons for?

My scientific brain is literally screaming in pain at so these thermodynamics driven processes show us the direction of time

Oh lord no. No no no.

Original poster
M3lon · 17/07/2018 22:28

Tana it certainly does spirals...but it would do that even if it were a uniform block the same shape.

OP posts:
FlaviaAlbia · 17/07/2018 22:28

I feel strangely let down by the answer. I think I'll have to do something messy and explosive like bottle rockets tomorrow to compensate Grin

Original poster
M3lon · 17/07/2018 22:28

real oh dear...why do you object?

entropy and the arrow of time is pretty well established?

OP posts:
Original poster
M3lon · 17/07/2018 22:29

flavia I knew it! Find a gyroscope....they are pretty cool!

OP posts:
Etymology23 · 17/07/2018 22:29

RealMary I think what the op is saying is that we know instinctively that things usually tend towards disorder (waves knock down sand castles, the wind and weeds destroy abandoned houses, food colouring disperses in water) and that this gives us an instinctive sense of time?

VanillaSugar · 17/07/2018 22:30

OP you know the cornflour : water in a cup and you can bash it and it's solid?

How much cornflour would I need to walk over water in a swimming pool?

AllyMcBeagle · 17/07/2018 22:37

if anyone has any other household item physics related mysteries then do ask away!

Clingfilm. It's made of magic right? Grin

Original poster
M3lon · 17/07/2018 22:39

Vanilla Am I allowed to take some of the water out?

If its a 25 meter pool then...

25102 cubic meters. 3/4 of which is cornflour by volume...and its half the density of water...so about 60, 000 kilos.

OP posts:
Original poster
M3lon · 17/07/2018 22:41

clingfilm....made of lots of very long, very tiny chains....and entropy (which is pretty magical).

OP posts:
SittHakim · 17/07/2018 22:44

No sensible contribution to the thread, but I just wanted to mention that the word for a substance that behaves like the cornflour/ water mixture (i.e. some of the properties of a solid and some of a liquid) is an oobleck. Isn't it a brilliant word?